Represents the number of shares held as a percentage of the total shares outstanding at the end of the period.

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Represents the percentage of the gross carrying value of real estate.

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Represents the service agreements entered into by the entity for availing services from other entities.

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Amount of distribution received from equity method investee for return on investment, classified as operating activities. Excludes distribution for return of investment, classified as investing activities.

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This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

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Amount of income (loss) for proportionate share of equity method investee's income (loss).

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Balance held at close of period in number of shares.

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The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

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The number of real estate properties owned as of the balance sheet date.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Cash received on stock transaction after deduction of issuance costs.

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The number of shares issued or sold by the subsidiary or equity method investee per stock transaction.

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Per share amount received by subsidiary or equity investee for each share of common stock issued or sold in the stock transaction.

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Related Person Transactions (Details) $ / shares in Units, $ in Thousands	1 Months Ended		3 Months Ended		6 Months Ended
	Jul. 31, 2020 USD ($) $ / shares shares	Jun. 30, 2020 USD ($) travel_center agreement hotel shares	Jun. 30, 2020 USD ($) travel_center agreement hotel shares	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) travel_center agreement hotel shares	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Related Party Transaction [Line Items]
Equity in earnings (losses) of an investee			$ (2,218)	$ 130	$ (2,936)	$ 534
Travel Centers of America \| RMR LLC
Related Party Transaction [Line Items]
Shares included in investment securities (in shares) \| shares		298,538	298,538		298,538
Noncontrolling interest, ownership percentage		3.60%	3.60%		3.60%
Sonesta Int'l Hotels Corp
Related Party Transaction [Line Items]
Noncontrolling interest, ownership percentage		34.00%	34.00%		34.00%
Subsequent event \| Travel Centers of America
Related Party Transaction [Line Items]
Price of shares (in dollars per share) \| $ / shares	$ 14.00
Subsequent event \| Public Stock Offering \| Travel Centers of America
Related Party Transaction [Line Items]
Shares purchased (in shares) \| shares	500,797
Purchase price	$ 7,011
Travel centers
Related Party Transaction [Line Items]
Number of properties owned \| travel_center		179	179		179
Travel Centers of America
Related Party Transaction [Line Items]
Lessee as percentage of gross carrying value of real estate		26.60%	26.60%		26.60%
Shares included in investment securities (in shares) \| shares		684,000	684,000		684,000
Percentage of total shares outstanding		8.20%	8.20%		8.20%
Travel Centers of America \| Travel centers
Related Party Transaction [Line Items]
Number of properties owned \| travel_center		179	179		179
Sonesta Int'l Hotels Corp
Related Party Transaction [Line Items]
Number of properties owned \| hotel		53	53		53
RMR LLC \| Amended and restate business management agreement
Related Party Transaction [Line Items]
Number of management service agreements \| agreement		2	2		2
Affiliates Insurance Company
Related Party Transaction [Line Items]
Equity method investments, carrying value		$ 12	$ 12		$ 12		$ 298
Liquidating distribution		$ 286
Equity in earnings (losses) of an investee				$ 130		$ 534